1. Field of the Invention
The present invention relates to an electrical connector, and particularly to an electrical connector having a shell for mounting the connector on a printed circuit board.
2. Description of Related Art
Electrical connectors for being mounted to printed circuit boards, typically have contact leads that extend through plated through holes or have leads that electrically engage contact pads on the surface of the printed circuit boards. Locating pins or posts are usually molded into the housing and arranged to enter into holes in the printed circuit board for accurately positioning the connector. These locating posts, sometimes include features that grip the printed circuit board to hold the connector in place. Mounting clips can also be used to both locate and hold the connector in place on the printed circuit board. Such a connector is disclosed in U.S. Pat. No. 4,645,287 which is issued on Feb. 24, 1987 to Olsson. The ""287 patent discloses an electrical connector having surface mount contact leads that engage contact pads on the surface of the printed circuit board. The housing of the connector has a U-shaped groove formed adjacent to an end thereof and a U-shaped clip is closely received within the groove. The two clips have ends that extend into holes in the printed circuit board for both precisely locating the contact leads on the contact pads and securely holding the connector on the printed circuit board. This type connector requires mounting space on the surface of the printed circuit board that is equal to the size of the connector, and requires separate U-shaped clips that must be assembled to the connector before mounting the connector to the printed circuit board. In certain cases such connectors can be mounted to an edge of a printed circuit board, thereby saving board surface area for other board mounted components. Electrical connectors that are mounted to an edge of a printed circuit board, typically, utilize pins that are molded with the housing of the connector to fit into holes in the printed circuit board to accurately locate the connector so that the contact leads thereof can accurately engage with contact pads on or plated through holes in the printed circuit board. Additionally, spring clips, or similar devices, enter into other holes in the printed circuit board for firmly holding the connector housing to the printed circuit board. Such an electrical connector is disclosed in U.S. Pat. No. 5,334,049 which is issued on Aug. 2, 1994 to Kachlic et al. The ""049 patent discloses an electrical connector having an insulative housing that includes a pair of flanges resting on the surface of the printed circuit board. A locating pin extends from each flange into a respective hole in the printed circuit board for positioning the connector. Each flange has a cavity receiving a metal hold down clip that includes a barbed portion extending into a hole in the printed circuit board. The metal hold down is deflected when it is inserted into the hole so that there is a continuing force urging the flanges of the connector housing to engage with the surface of the printed circuit board. While this type of connector requires less circuit board surface area for mounting, it nevertheless requires some space for the flanges, and requires both locating pins and metal hold down to effect a proper mounting.
Furthermore, electrical connectors are widely used in computers. When such connectors are used in high speed data transmission applications, the amount of electromagnetic or radio frequency interference increases. Such an electrical connector is disclosed in U.S. Pat. No. 6,364,700 which is issued on Apr. 2, 2002 to Zhu et al. This connector uses a shell stamped from a metal blank enclosing the housing for electromagnetic interference (EMI) shielding. A locking device is formed on each of two opposite side faces of the shell, each locking device including a pair of first locking legs and a pair of second locking legs. Either the first locking legs or the second locking legs have oppositely projecting protrusions for engaging with the printed circuit board, whereby the hole for receiving the first locking legs or the second locking legs has a large dimension. A large through hole in the printed circuit board causes difficulty to design the layout of the printed circuit board, particularly when the printed circuit board is small for use in a notebook computer.
What is needed is an electrical connector which can be securely mounted to an edge of a printed circuit board. A locking device for positioning and securing the connector to a printed circuit board is formed on a shell of the connector, so that no separate clip or other part to effect the mounting of the connector is required. Ideally, an improved structure will serve to position the connector, secure it to the printed circuit board for soldering and provide with an EMI shielding at the same time. Furthermore, through holes defined in the printed circuit board for receiving the locking device should have a small size to facilitate the design of layout of the printed circuit board.
Hence, an electrical connector with a shell having an improved retention structure is required to overcome the above disadvantages of the prior art.
Accordingly, a first object of the present invention is to provide an electrical connector having an improved shell with a retention structure which can securely position the connector to a printed circuit board.
A second object of the present invention is to provide an electrical connector having an improved EMI shell with a retention structure for engaging in through holes of a printed circuit board, wherein the through holes can have a small size.
In order to achieve the objects set forth, a shielded connector mounted on a printed circuit board includes an insulative housing, a set of conductive terminals, and a conductive shell. The housing includes a top wall, a bottom wall, a front wall, a rear wall, and opposed sidewalls which together define an interior space. The terminals are received in the interior space. The shell enclosing the housing includes two retention devices on each of two opposite sides thereof. Each retention device includes a hook and a beam extending through the housing. The hook is longer than the beam and has a bottom free end forming a protrusion at a side edge thereof. The protrusion is adapted for engaging in a hole in the printed circuit board.